SUMMARY OF THE REMEDIATION TECHNOLOGIES
DEVELOPMENT FORUM
IN-PLACE INACTIVATION AND NATURAL ECOLOGICAL
RESTORATION
TECHNOLOGIES (IINERT) SOIL-METALS ACTION TEAM
CONFERENCE CALL
June 22, 1998
On Monday, June 22, 1998, the following members of the IINERT Soil-Metals Action Team met in a conference call:
Bill Berti, DuPont Life Sciences (Co-chair)
Sally Brown, U.S.
Department of Agriculture (USDA)
Gary Pierzynski, Kansas State
University (KSU)
Also present was Christine Hartnett of Eastern
Research Group, Inc. (ERG).
SAMPLE COLLECTED FROM KANSAS ARMY AMMUNITION PLANT AT PARSONS
During the previous conference call, Andrea Austin had agreed to collect and sieve a soil sample from the Kansas Army Ammunition Plant. Bill Berti noted that Austin is having difficulty mixing and sieving the sample because the soils are very wet. (He noted that Kansas has received a large amount of rainfall recently.) Gary Pierzynski asked whether the IINERT Team can use the sample if Austin simply shovels it into a barrel without mixing and sieving it. Berti said he would discuss the issue with Jim Ryan.
ECO SOIL SCREENING LEVEL WORKSHOP
Berti said that he attended an Eco Soil Screening Level Workshop in Denver, Colorado. The aim of the workshop was to identify soil contaminant concentrations that do not pose excessive risk to the environment. Some of the current screening levels, Berti noted, have limited practical value. Based on shrew dosing studies, for example, aluminum soil concentrations of 20 mg/kg appear to pose an ecological hazard. Berti stressed that we would all be dead if 20 mg/kg really did pose an excessive hazard, because aluminum is a common constituent in clays of soils and concentrations 1,000 times greater than this are common.
Pierzynski said he was encouraged that efforts are underway to identify screening levels. He said that several risk assessors, particularly those representing fertilizer companies, are erroneously using the 503 regulations to assess ecological risk. Sally Brown noted that the 503 regulations were developed to evaluate biosolids. Using them to evaluate ecological risk, Brown stressed, is inappropriate. She said that there is no way to determine whether using the 503 regulations for an ecological assessment is under- or overprotective, because the 503 regulations were derived for a different matrix. Pierzynski agreed, noting that the 503 regulations do not address all the pathways and materials needed for an ecological assessment.
Berti asked whether the 503 regulations could serve as a good starting point for the Eco Soil Screening Level Workshop to build on. Brown said the regulations are an appropriate model, but Pierzynski said they should not be relied on too heavily. Pierzynski warned against simply applying a “fudge factor” to the 503 regulation numbers.
UPDATE ON ACTIVITIES AT THE JOPLIN TEST SITE
Berti noted that he and Brown collected samples from the Joplin field site in mid-May. Samples included:
Brown noted that the USDA’s rat feed study is still in progress. She said bone samples still must be analyzed. Berti agreed to call Rufus Chaney for information on results collected to date.
The conference call participants discussed future activities at Joplin. Pierzynski asked whether Mark Doolan has made a decision about new activities. Pierzynski had heard that Doolan would make a decision after receiving the results of one of the University of Missouri’s swine studies. Neither Brown nor Berti knew whether Doolan has made a decision. Brown noted two studies that have been recommended at Joplin:
KSU’S ACTIVITIES
As mentioned during the last conference call, Pierzynski and a graduate student initiated a preliminary incubation test to see whether preacidifying soil serves to enhance the reduction of lead bioavailability when phosphorus is added to a system. Pierzynski had been puzzled by the fact that no differences were noted between different test treatments after 1 week of incubation with the SBRC in vitro test. Pierzynski said that he talked to Nick Basta about the lack of differences between treatments. Basta suggested that the intestinal phase of the extractant is more sensitive to treatment effects than the gastric phase. After hearing this suggestion, Pierzynski and his graduate student performed the in vitro test using the intestinal phase and found observable differences between treatments. Given this finding, Pierzynski suggested that the extractant used in the SBRC protocol could be too harsh and inappropriate for amended soil samples. Brown asked Pierzynski whether differences between treatments would be noted if the pH of the gastric phase were raised. Pierzynski said that he raised the pH from 1.5 to 2.0 but still observed no differences.
Pierzynski noted that he and the graduate student have also been investigating treated soil to determine how amended soils serve as a growth medium. Specifically, they have been evaluating which acid is best to use for the preacidification step. (Pierzynski said that he uses acid to bring soil pH down to 5, then adds phosphorus and uses calcium oxide to raise the pH.) Pierzynski said that hydrochloric acid is best for reducing lead bioavailability, but he warned that it produces saline soils. Phosphoric acid, he said, produces less saline soils.
Berti noted that Pierzynski had identified some questions regarding the SBRC protocol during the last conference call. Pierzynski has not had a chance to talk with Drexler about these questions yet.
During the last conference call, Pierzynski had expressed interest in having his graduate student perform the in vitro test using the National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 2711 (Montana soil). Pierzynski has received some of the SRM sample but has not yet had a chance to perform analyses.
MISCELLANEOUS
Brown noted that Harry Compton (EPA) received an urgent message about a lead-contaminated site in Thailand. Brown said that the site has mine tailings that are floating down a river. Brown told Compton that the IINERT Team might be able to assist with this site.
Berti noted that a group of dead swans were found on a farm in Delaware. Investigators have determined that the deaths are related to ingestion of lead shot from a shooting range. Berti asked if there was a simple way to remove lead shot from the surface. Pierzynski suggested using a sod harvester.
Brown said that she is leaving USDA. As of October 1, 1998, she will be with the University of Washington’s College of Forest Resources.
NEXT CONFERENCE CALL
The next conference was originally scheduled for July 20, 1998. Brown said that she would not be able to participate that day. Berti agreed to check people’s schedules before finalizing the date of the next call.